| The spatial distribution of droplets in the interior of the plant is one of the important indicators for validating the quality of the spray.In the process of spray performance evaluation and spray parameter setting,a large number of spray operation tests must be conducted,the result of spray operation tests cannot be replaced by the simulation software simulation results.The current test for spatial droplet deposition distribution is mainly conducted in the field.Since a wide range of crops,and morphology of many species affected by the environment and species,the research process is complicated and time consuming.Therefore,on the basis of the distribution of droplet deposition at domestic and foreign,this paper proposes the research method of porosity similarity from the perspective of optical porosity(abbreviated as porosity),and designs a three-dimensional space standardization device which is similar to crop static porosity based on this method,which is simulated instead of crop,at the same time,and different static porosities under different growth patterns of different crops or crops are characterized by varying the porosity of the device..It is used to complete crop tests under different growth patterns.The amount of sedimentation,in the early stage of the project group(Zuo Wenlong,2015;Chen Rongkang,2017),conducted a large number of CFD model simulations and comparison experiments with real plants to prove that the CFD model simulation can objectively reflect the experimental results of real crops.In the CFD,the spray simulation model under different static porosity was established,and the spatial distribution of the droplets under different porosity was obtained through simulation calculation,at the same time,the droplet deposition experiment under different static porosity was conducted and the statistics of each layer were calculated.Simultaneously,the droplet deposition experiment under different static porosity was conducted and the statistics of each layer were calculated.and therefore,combined with simulation results and The experimental results quantitatively analyze the influence of porosity on the spatial distribution of droplet deposition.The main work has been completed as follows:1.From the transportation of droplets in crop,the crop were abstracted as porous media,and according to the porosity characteristics of porous media,a method for the similarity of porosity was proposed,taking cotton plants as an example.according to this method,a plant similar static porosity similarity device of different plant types was established.2.Computational fluid dynamics(CFD)modeling and simulation of a three-dimensional spray simulation model for a static porosity similarity device,and analysis of the motion simulation results of the droplet at pores and non-porosity.3.Simulation analysis of the remaining droplet volume and distribution of residual droplets after the droplets pass through each layer under different static porosity,and the distribution of droplets deposited on each layer is analyzed from the penetration of droplets.Simulation results It shows that the different porosity affects the penetrability of droplets obviously.4.Set up different porosity similarity devices and conduct spray tests,spray test conditions as same as the simulation test conditions,using water sensitive paper statistics the droplets deposition,and comparing with simulation statistics of deposition,the simulation results consistent with the test results,the error is within 16.5%,shows that the droplets deposition test device of static porosity similar can realize the analysis of spatial distribution of droplets deposition,spray performance verification for the prototype and spray parameters set provides a universal test device;Finally combining with the results of simulation and test,analyzing each layer and the overall deposition under different static porosity,and the results showed that the porosity has significant effect on the droplets deposition distribution,it provides new ideas or perspectives for studying the distribution of droplet deposits within the crop. |
